In the related art, a water filtration system of a water purifier can usually obtain one kind of water quality. However, in addition to drinking water, a user also needs other domestic water, such as water for washing clothes, so the water filtration system, which can only obtain one kind of water quality, cannot satisfy a requirement of the user. Furthermore, when the user needs a large amount of water, the water filtration system cannot produce a large amount of water for use by the user in a short period of time.